http://math.ucr.edu/home/baez/physics/Relativity/GR/centre.htmlWhere is the centre of the universe?There is no centre of the universe! According to the standard theories of cosmology, the universe started with a "Big Bang" about 14 thousand million years ago and has been expanding ever since. Yet there is no centre to the expansion; it is the same everywhere. The Big Bang should not be visualised as an ordinary explosion. The universe is not expanding out from a centre into space; rather, the whole universe is expanding and it is doing so equally at all places, as far as we can tell.In 1929 Edwin Hubble announced that he had measured the speed of galaxies at different distances from us, and had discovered that the farther they were, the faster they were receding. This might suggest that we are at the centre of the expanding universe, but in fact if the universe is expanding uniformly according to Hubble's law, then it will appear to do so from any vantage point.If we see a galaxy B receding from us at 10,000 km/s, an alien in galaxy B will see our galaxy Areceding from it at 10,000 km/s in the opposite direction. Another galaxy C twice as far away in the same direction as B will be seen by us as receding at 20,000 km/s. The alien will see it receding at 10,000 km/s: A B CFrom A 0 km/s 10,000 km/s 20,000 km/sFrom B -10,000 km/s 0 km/s 10,000 km/sSo from the point of view of the alien at B, everything is expanding away from it, whichever direction it looks in, just the same as it does for us.The Famous Balloon AnalogyA good way to help visualise the expanding universe is to compare space with the surface of an expanding balloon. This analogy was used by Arthur Eddington as early as 1933 in his book The Expanding Universe. It was also used by Fred Hoyle in the 1960 edition of his popular book The Nature of the Universe. Hoyle wrote "My non-mathematical friends often tell me that they find it difficult to picture this expansion. Short of using a lot of mathematics I cannot do better than use the analogy of a balloon with a large number of dots marked on its surface. If the balloon is blown up the distances between the dots increase in the same way as the distances between the galaxies."The balloon analogy is very good but needs to be understood properly—otherwise it can cause more confusion. As Hoyle said, "There are several important respects in which it is definitely misleading." It is important to appreciate that three-dimensional space is to be compared with the two-dimensional surface of the balloon. The surface is homogeneous with no point that should be picked out as the centre. The centre of the balloon itself is not on the surface, and should not be thought of as the centre of the universe. If it helps, you can think of the radial direction in the balloon as time. This was what Hoyle suggested, but it can also be confusing. It is better to regard points off the surface as not being part of the universe at all. As Gauss discovered at the beginning of the 19th century, properties of space such as curvature can be described in terms of intrinsic quantities that can be measured without needing to think about what it is curving in. So space can be curved without there being any other dimensions "outside". Gauss even tried to determine the curvature of space by measuring the angles of a large triangle between three hill tops.When thinking about the balloon analogy you must remember that. . .* The 2-dimensional surface of the balloon is analogous to the 3 dimensions of space.* The 3-dimensional space in which the balloon is embedded is not analogous to any higher dimensional physical space.* The centre of the balloon does not correspond to anything physical.* The universe may be finite in size and growing like the surface of an expanding balloon, but it could also be infinite.* Galaxies move apart like points on the expanding balloon, but the galaxies themselves do not expand because they are gravitationally bound.... but if the Big Bang was an explosionIn a conventional explosion, material expands out from a central point. A short moment after the explosion starts, the centre will be the hottest point. Later there will be a spherical shell of material expanding away from the centre until gravity brings it back down to Earth. The Big Bang—as far as we understand it—was not an explosion like that at all. It was an explosion of space, not an explosion inspace. According to the standard models there was no space and time before the Big Bang. There was not even a "before" to speak of. So, the Big Bang was very different from any explosion we are accustomed to and it does not need to have a central point.If the Big Bang were an ordinary explosion in an already existing space, we would be able to look out and see the expanding edge of the explosion with empty space beyond. Instead, we see back towards the Big Bang itself and detect a faint background glow from the hot primordial gases of the early universe. This "cosmic microwave background radiation" is uniform in all directions. This tells us that it is not matter that is expanding outwards from a point, but rather it is space itself that expands evenly.It is important to stress that other observations support the view that there is no centre to the universe, at least insofar as observations can reach. The fact that the universe is expanding uniformly would not rule out the possibility that there is some denser, hotter place that might be called the centre, but careful studies of the distribution and motion of galaxies confirm that it is homogeneous on the largest scales we can see, with no sign of a special point to call the centre.The cosmological principleThe idea that the universe should be uniform (homogeneous and isotropic) over very large scales was introduced as the "cosmological principle" by Arthur Milne in 1933. Not long before that, it had been argued by some astronomers that the universe consisted of just our galaxy, and the centre of the Milky Way would have been the centre of the universe. Hubble put an end to that debate in 1924 when he showed that other galaxies exist outside our own. Despite the discovery of a great deal of structure in the distribution of the galaxies, most cosmologists still hold to the cosmological principle either for philosophical reasons or because it is a useful working hypothesis that no observation has yet contradicted. Nevertheless, our view of the universe is limited by the speed of light and the finite time since the Big Bang. The observable part is very large, but it is probably very small compared to the whole universe, which may even be infinite. We have no way of knowing what the shape of the universe is beyond the observable horizon, and no way of knowing whether the cosmological principle has any validity on the largest distance scales possible.In 1927 Georges Lemaître found solutions of Einstein's equations of general relativity in which space expands. He went on to propose the Big Bang theory with those solutions as a model of the expanding universe. The best known class of solutions that Lemaître looked at were the homogeneous solutions now known as the Friedman-Lemaitre-Robertson-Walker (FLRW) models. (Friedmann found the solutions first but did not think of them as reasonable physical models). It is less well known that Lemaître found a more general class of solutions that describe a spherically symmetric expanding universe. These solutions, now known as Lemaître-Tolman-Bondi (LTB) models, describe possible forms for a universe that could have a centre. Since the FLWR models are actually a special limiting case of the LTB models, we have no sure way of knowing that the LTB models are not correct. The FLWR models may just be good approximations that work well within the limits of the observable universe but not beyond.Of course there are many other even less uniform shapes the universe could have, with or without an identifiable centre. If it turned out to have a centre on some scale beyond the observable universe, such a centre might turn out to be just one of many "centres" on much larger scales, just as the centre of our galaxy did before.In other words, although the standard Big Bang models describe an expanding universe with no centre, and this is consistent with all observations, there is still a possibility that these models are not accurate on scales larger than we can observe. We still have no real answer to the question "Where is the centre of the universe?".

Brigitte Nenet woke to two immediate impressions. The tiny tiny movement of baby Lenarra inside of her, just 18 weeks old and already starting to assert herself. Then there was Marty, husband and now father, spooning behind her. She glanced at her phone on the nightstand and knew why she was awake. There was a text waiting for her. Three in the morning and someone was wanting her. She sighed heavily and reluctantly reached out to it. She hesitated once more before reading it, knowing that she'd never get back to sleep if she did. Finally she read it and put the phone back down. Damn. It was too important to ignore. Too interesting to go back to sleep. She set the phone down and peeled herself away from Marty. Too early. Just too early. Getting out of bed without waking Marty was easy. That man could sleep through anything, she thought. Lucky.

The apartment was already warm at 70 degrees, but that was Tehran in July. Still, she'd need coffee and quiet time to digest the news. And she'd also need a few minutes of what she thought of as talk with her daughter. Marty had bought her an old fashioned journal, beautifully handcrafted in the old way with papyrus. It was expensive and impractical in this age of electronic everything. But it was also a tangible link to the old world and a reminder that they shared a love for the written word. And of course, the government had no way to track and catalogue words written in ink upon papyrus. That papyrus journal had become her continuing letter to Lenarra to be opened at her daughter's discretion. So she sat at the table, listening to Marty snore, with a coffee by her side, the journal and pen in front of her, and baby Lenarra resting.

"Lenarra, the world I live in is a dark place sometimes. It's scary and challenging. Sometimes it's hard to know who to fear the most. The government that protects us, or those from whom we need that protection. We have freedom and peace. People who used to hate each other are now brothers and sisters and husbands and wives and lovers. But the price of that freedom is sometimes fear, and the price of that peace is the knowledge that there are eyes everywhere. You wouldn't think that the two conditions could coexist, but somehow they manage to. We are safe here on Earth, but we are also confined. You will not live in that world. Your father and I will either change it for you, or we will take you to another. You will live in a world that is not constrained to the trade-off of peace for freedom. Tomorrow I'll tell you about your father. You'll fall in love with him, just like I did." With that she closed the book and picked up her phone. The text was there, dragging her from the quiet personal conversation with Lenarra to the inescapable electronic today with its shocking news.

"Good morning," Marty said from the doorway. "Technically it is morning. So what's up?"

She drank her coffee down quickly and handed him her phone. "The ESA is going to the Oort Cloud."

"So?"

"According to Maury they detected a radio pulse from within the cloud. Something's out there."

"Ridiculous."

"Marty, they've already slated a mission. They're apparently fighting for funding, but they'll go one way or another. And they wouldn't if there wasn't anything out there."

"The Oort Cloud is nothing but ice and dirt."

"And it's a hundred light-days away. Marty, they have a reason to go, which means that we have a reason to get there first."

"We," Marty said.

"Yes, we. Both of us."

"Babe, when you say 'us' you're talking about the three of us."

She didn't try to hide her annoyance. "Why are you doing this?"

"I'm not trying to be an ass, Brig. I know you're a doctor and you know what's best for her more than I do. But if we're going to get out there, that far, we can't go at sublight speed and expect to get there first. An ESA cruiser will get there in minutes. At relativistic speed, at .99 the speed of light, we won't get there for, what, a hundred days? More maybe."

"And since civilians are prohibited from FTL flight in-system..."

Marty thought about the coffee maker on the counter. He really wanted a coffee for this discussion, but he didn't want to take the time to make it. "Harry Est brought in a Tsantarii warp sled a few days ago. It's inside an asteroid that we can get to in about six hours."

Brigitte walked to the coffee maker and started it for Marty. "Where did Harry get a Tsantarii warp sled?"

"Where does anybody get an illegal warp sled? From a friend of a friend of a contact who got it from somewhere we don't want to think about." After waiting for the cup to brew, he took it and sipped at it. "The sled will adapt to a sublight rental Prospector we can shuttle up to from Riyadh."

"You sound like this was your idea from the start."

"No, of course not. I was just thinking that if we decide to get out before-."

"Lenarra?"

"If she isn't born on Earth they'll have no jurisdiction over her."

She kissed him on his forehead. "I know. I don't know if we're quite there yet. I like Earth. I don't think it's beyond fixing. But we'll keep the sled. Just in case."

"Okay," he answered. "I'll call Harry and make sure it's ready to go."

"Good," she said. "We've got an eighteen hour launch window for our ice fishing. That leaves time of breakfast."

By three o'clock that afternoon, they were in a rented Ev'nan-registered Prospector utility craft designed for light asteroid mining and adaptable to a number of makes and models of attachments. Whether the enigmatic Ev'nan had intended their Prospectors to be adaptable to Tsantarii warp sleds or the even more exotic and xenophobic Tsantarii used the same modular docking components that the rest of the galaxy employed was uncertain. But the Prospector locked easily and naturally inside the spherical sled, and Marty and Brigitte were soon outside the orbit of Pluto and heading for rest of the Kuiper belt. "Prospector power cut off," Brigitte said from the utility craft's control panel. "In three- two- one-. Mark."

"Engaging warp," Marty said. The quantum drive reached out elemental fingertips, folding space/time from an empty space just past Pluto to the far more distant shell of icy bodies that formed the Oort Cloud. And suddenly, with neither fanfare nor fireworks, they were there. "Everything still good babe?"

Brigitte punched up the video feed on the Prospector's monitor. It showed a computer-generated image of the spherical warp sled hanging over an icy rock. "We are where we're supposed to be. We have power and sensors. And Lenarra is quiet."

"Good good good," he answered, only then realizing that his breath was short. "Detaching clamps. Retracting door. You'll be free in a sec."

"Acknowledged. As soon as the Prospector has separated I'll activate short range sensors. That should take me right to it." The small craft shuddered as the physical connection between the sled and the Prospector was severed. Then it shuddered again as magnetic constrictors were released. That was the last connection between the two craft, and now it was completely safe to activate the ship's onboard power systems. One large switch did that, and then she flipped a series of smaller ones, activating short range sensors and exterior cameras. That brought a flood of light to the monitor that slowly slid out of view. The sled was opening its maw and allowing the Prospector to slip out.

Half an hour later, she was piloting the small craft just above the icy surface with no radio transmissions detected. If the Earth Star Empire's long range sensors were pinged from this far away, it should be easy to find close up. They'd even heard it from just past the orbit of Mars. "How long ago was the last burst?"

"That's not a simple question, babe." Marty answered. "Taking into account the fact that it was an old fashioned radio signal that took months to reach the sensor net in the Mars Defense Perimeter, really, there would have been several while we were skipping over subjective time."

"Dammit Marty, I don't want a science lesson. When was the last burst?"

"Subjectively? Observationally? Based on anecdotal information? Because it's really not a simple, easy answer sitting out here."

"Here's a simple, easy question for you," she knew he was playing with her, and she struggled to keep the amusement out of her voice. "Based on subjective, anecdotal information, how long ago did this thing send a burst?"

She heard him chuckle over the comm link. "Sorry. As far as I can tell, just under three hours ago."

"Okay. And do we know how long before that?"

"Just a second." There was silence, during which she assumed he was checking pirated logs. "Yep. Three point one-four. In fact, there's a long string of regular bursts at the same interval."

"So if it stays constant, we should get another in just about a half hour?"

"Yes. You know, Brig, this begs a question."

"What's that?"

"What are we going to do with it?"

"That depends on what it is," she answered as her eye remained glued to the round radar-like sensor display. "Who knows, really?"

"My point being, if we do anything to interrupt its transmissions-".

"If we even manage to get inside of whatever it is-".

"Then they'll know that someone's out here and beat them to it."

"Yes," Brigitte said without elaborating.

"We'll have to disappear for a while."

"I know. How good do you think this warp sled really is?"

"And the Prospector that we'd be stealing from an honest business?" Marty hated stealing anything. "I don't know. There is Wolf 359 we could probably safely reach. Alpha Centauri B. Proxima Centauri. Epsilon Eridani. Tau Ceti. Sirius A. Procyon, 61 Cygni A and B,. There are a few choices."

"Most of which with heavy Earth presence."

"Most of which, yeah," he answered. "But Alpha Centauri B and Tau Ceti not so much."

"The failed colony sites," she answered. "Yes. We might have to think about that. Stop for a while, make a few decisions." She yawned. "How much longer?"

"Not long. A few minutes."

"Okay, here's a question for you, science man. Are we on the right side of this rock to pick up the signal?"

"Yes mother, we are."

"Good," she answered. "I'm getting tired of waiting." A rumbling in her belly echoed her feelings. "And so is Lenarra."

"Two women now," Marty said. "I don't stand a chance."

"No you don't." She smiled at the thought. "But seriously. You know, we don't even know how big this thing is. We might not be able to take it with us."

"We don't even know what it is or what it means."

"No, but it's important," she said. "And we'll know soon enough."

"Yes," he said. "It should be any time now."

"Good." Then there was a spike of white on her sensor screen. "Bingo!" She tapped a control to save the image, and superimposed it on a topographical map of the rock. "Okay. Yeah I'm actually pretty close. Just need to drop down." She manipulated the simple joystick built into the column, dropping the utility craft to within twenty feet from the surface. "Coming up on the source in just a minute-".

In the warp sled, Marty waited with mounting frustration as she was silent. He wanted to be down there. "Hey? What's up? Talk to me."

"It's okay," she said, sounding busy and distracted. "Hang on. I'm at the surface. Just drilling a small hole."

"Be careful!"

"Marty, chill out. It's okay. I need to get under the ice to get to this thing."

Brigitte mumbled under her breath below the audio pick-up range. God bless him, Marty was a wonderful man. Worries like a mother hen, but he'd be a wonderful father if she didn't kill him first. She switched on the extender drill and dropped it towards the icy surface. Then she hesitated. This really was it. A big moment. She slowly dipped the control stick, and the drill hit the surface. "We're in. Just need to go down about a foot." As the drill dug into the ice, she watched the scanner. "What are these things made of?"

"Water. Methane. Ammonia. A few other things. Why?"

"This one isn't. It's metal of some kind. Weird. It's flying apart as the drill goes through it, like its meant to. Like an ablative shield of some kind. Designed to absorb damage to protect something-"

"Stop!" Marty sounded scared. "Is this an Imperial sensor post?"

"No, it's not. This metal, whatever it is, didn't come from Earth or any of its holdings. If it did the scanner would identify it. Marty it's okay. It's not Imperial. But I don't know what it is." She stopped to take a breath and think. "Okay. I'm going to get a sample. Wait." A small flexible tube dropped out of the bottom of the craft, snaking the few feet to the surface and the hole that she'd drilled. Like the vacuum in their apartment, it pulled loose debris up, dropping it into a sealed compartment. "I've got the sample. And I'm close to whatever it was that sent the transmission. Hang on." As the vacuum withdrew into the craft, the drill continued. Then it stopped. "Got it. Marty, it's small. Round. About six inches across. Just sitting there in a small hollow."

"And that's the source?"

"Yes. No doubt about it. No apparent power source or connections, but this is it." She dropped another extender from the bottom of the craft. This one was fitted with manipulator digits, suitable for picking up delicate objects. "I'm taking it up."

Inside the darkened cockpit of the warp sled, Marty felt his heart beating hard. Her calm voice from the Prospector only seemed to agitate him more. "You'd better set coordinates for a jump," she said.

"Alpha Centauri B?"

"I guess so. But not to stay. We're going home, babe."

"I know. As soon as you have that thing secured, come back up here. I want to get away fast." Without waiting for her answer, he scanned the Prospector. He just wanted to know that she was okay, and Lenarra with her. Then his breath caught. "Brigitte?"

Star Empires Chronicles will be a occasional feature. A serialized story previewing the larger works. Think of it as a series of short television episodes paralleling a movie series. Something science fiction fans can identify with. Look for regular episodes right here...

Something I've just learned for my literary ice-fishing expedition to the Oort Cloud. Even traveling at relativistic speed, (speeds approaching the speed of light) it would take you more than a hundred days to reach the interior of the Oort Cloud (I'm figuring about a fifth of the way in), which is the 'shell' of icy material and comets at the outer edge of our solar system. The Oort Cloud is believed to be about 3,000 to 100,000 AUs (an AU is the distance from the Earth to the sun, or about 93 million miles). By comparison, Pluto is about 40 AUs distant from the sun. StarEmpires is not meant to be a science lesson, but if you aren't careful, you might learn something along the way.

Kapact watched the embers from his estate flying up into the sky and thought briefly about how long the property had been in his family. Centuries by human reckoning. So far back that exact records didn't exist. Then he turned to his son. "You have to understand, I was on a mission. It wasn't going well. None of them go well these days. But we still needed to function, and in order to function we needed to sleep. And in order to sleep, sometimes I needed the drink. Some of the younger crew, the unmarried crew found other ways to release the tension. But I didn't have any of that of course. And your mother couldn't have known and I wouldn't have told her." He avoided Kat'lya's eyes while discussing such things. He knew what he needed to know about biology, and his relations with the boy's mother weren't up for discussion. "Anyway, we were losing a battle and I called for a retreat. That's why I was declared a coward and beaten in the Aisa ceremony."

"Dad it doesn't matter."

Kapact felt the young eyes on him and he continued to look away. "It does matter. It matters to me, for where I'm going next and what I have to do. And it matters to you because you have to live here with my name attached to you. And it matters to her, because it cost her her life." Kapact felt his son's eyes boring into the back of his head, and finally he turned because he had no choice. "The Yeshai meteor shower begins in two days. That's when we'll say goodbye to her."

Two days later, Kapact was in the last place he wanted to be, seeing something he thought he'd never see again. Her. "Why am I here?" He demanded. "Why is she here?" He looked down at her, nearly wrapped in the ceremonial fur that would accompany her to the Yeshai asteroid field. And yet, he'd thought of her as a thing. No longer his wife. No longer the mother of his child. Just a thing that used to be a woman that he'd loved. The wife of a disgraced officer.

"I'm sorry, Captain. There's a complication." The doctor stood next to the pastor , who somehow seemed to silently look down on Kapact from his diminutive height. The woman doctor cleared her throat with a sound like a growl. "Were you aware that your wife was pregnant?"​

Author

I'm one of those people who writes like most people read. I'm always writing something. The book on my nightstand is one that I'm writing. Beyond thaat I'm just like you, just like everyone else in my own unique way. And I live and work in Las Vegas with three cats and enjoy a loving long distance relationship with a beautiful, wonderful lady.